Guide wires are currently used to position catheters within the arterial system for procedures such as angioplasty and angiography. The guide wire is typically advanced within the vasculature of a patient to a desired position, followed by a catheter, advanced over the guide wire. It is often necessary to remove a first catheter from the patient and advance a second catheter into position. When the catheter is in position within the patient, a proximal segment of guide wire extends from the patient. The extending proximal segment can be grasped and used to maintain the position of the guide wire.
Withdrawing a catheter over an in-place guide wire typically requires a guide wire extending from the patient for a length at least as long as the catheter guide wire lumen. This is required so as to present an uncovered portion of the guide wire to grasp. "Over-the-wire" catheters have a guide wire lumen over substantially the entire catheter length. "Single-operator-exchange" catheters can have a shorter guide wire lumen, extending only through the catheter distal region. Withdrawing an over-the-wire catheter over the guide wire would completely cover a standard length guide wire, presenting a problem. This problem has been dealt with in several ways.
The original guide wire can be withdrawn and replaced by a double length, exchange guide wire, providing a graspable guide wire portion during the exchange. This can complicate the procedure as the in-place guide wire must be removed and another inserted. Alternatively, a double length guide wire can be used from the start. This can be awkward as the portion of the guide wire extending from the patients body can be unwieldy, and may be unnecessary, if only the first catheter is needed.
In another method, an extension guide wire is provided and crimped or otherwise joined to the in-place guide wire, thereby creating a double length guide wire for effecting a catheter exchange. The crimping adds an additional step and requires the joining of two extremely small wires in the operating room. Crimping also raises the possibility of wire separation during catheter exchange. What remains to be provided is a guide wire that is not a double length guide wire, yet does not require the joining of an extension guide wire to effect an over-the-wire catheter exchange.